This invention relates to polyaspartate salt and more particularly to process improvements for preparing such polymer.
Crosslinked hydrolyzed polymers of L-aspartic acid are disclosed as superabsorbent polymers in U.S. Pat. Nos. 5,461,085 to Nagatomo et al and 5,525,703 to Kalota. L-aspartic acid is thermally polycondensed to polysuccinimide (PSI) and then dissolved in organic solvent or suspended in water and crosslinked by adding crosslinking agent to the solution or suspension. The product of the crosslinking reaction is then hydrolyzed, typically using aqueous caustic. According to these prior art patents, when PSI is crosslinked in organic solvent, it is first isolated before subjecting to aqueous hydrolysis. Improvements are continuously sought in simplifying processes for forming these industrially important products.